In U.S. Pat. No. 4,694,308 issued to C. S. Chan et al, there is disclosed and claimed a new and improved nickel barrier layer and nozzle plate assembly for use in thermal ink jet printheads. In this patent, there is described a composite nozzle plate with a nickel barrier layer portion and an outer nickel orifice plate portion, and these two portions are integrally formed in a two mask step electroforming process. The nozzle plate thus formed includes convergent orifice passageways which serve to minimize gulping and cavitation wear during an ink jet printing operation.
In U.S. Pat. No. 4,675,038 issued to James G. Bearss et al, there is disclosed and claimed a new and improved compound bore fabrication process for improving the orifice center-to-center spacing density in metal nozzle plates without requiring a corresponding reduction in nozzle plate thickness. Both of these commonly assigned patents are assigned to the present assignee and are incorporated herein by reference. Additionally, the actual electroforming process chemistry for plating the layers of nickel described in these two copending applications is described in more detail in the Hewlett-Packard Journal, Volume 38, Number 5, May 1985, also incorporated herein by reference.